USE OF THERMOPLASTIC SANDWICH MATERIAL FOR THE PRODUCTION OF VEHICLE BODIES

Abstract: This case concerns the use of laminates consisting of thermoplastic materials in the manufacture of car bodies/cabins and larger parts of such for vehicles. It is presumed that the application will be performed in one operation, preferably by means of rotational moulding. It is presumed that the materials in the different layers are bound to one another without the use of added adhesives/bonding agents. The application further consists of preferably varying qualities/colours in the different layers of the thermoplastic laminate.

Description: Use of Thermoplastic Sandwich Material for the Production of Vehicle Bodies This invention concerns the use of laminates in thermoplastic material for the manufacture of car bodies/cabins, or large uniform body parts for vehicles. For a long time work has been in progress on the wider use of plastics materials in the manufacture of vehicles and cars, with a view to reducing weight, reduc¬ ing corrosion problems and cutting costs. In recent years in particular intense efforts have been made in this field with regard to weight saving with the object of reducing energy consumption and thereby also reducing pollution. In most cases the plastics materials have completely different properties to steel which is used to a considerable extent, with considerations of strength, elasticity, temperature conditions, point loads, etc. in mind. As in most branches of industry the vehicle industry is also facing major chal- lenges with regard to future requirements for recycling of materials. In order to be able to implement an effective recycling of materials, the first requirement is that recyclable materials should be used to begin with and secondly that the product, parts or components should be designed in such a manner that they can be easily dismantled, returned to raw material and thereafter employed in an appropriate manner to form a new product. It is also important for this recycling process to have an acceptable economic profile. Another problem involved in the use of metallic constructions for body and cabin building is the substantial finishing process required for corrosion protection and surface treatment of the product. This is an elaborate and expensive process which in many cases also entails considerable environmental stresses. The present application for a functional patent redresses some of the above- mentioned problems and provides a practical and economic application of thermoplastics for the production of bodies and cabins, or large uniform parts of such. The use of laminated thermoplastic materials for the manufacture of bodies/cabins or large parts for vehicles will provide major advantages such as the fact that the product will be lighter than present constructions where substantial frameworks with welded panels generally also have to be built in order to fabricate a car body or body parts. By using a laminate construction of thermoplastics, properties will be obtained which have many advantages over the traditional construction materials and methods employed to-day. A layered construction of a body part provides possibilities for selecting the most suitable quality for the individual layers. In this way recyclable material can also be used in a rational manner, the outer layer, for example, being made of a pure/new material, while an inner layer is constructed of recycled material in which the requirements for purity, colour, etc. are of no importance and thus an additional second layer can be provided on the inside in different colours /qualities. It can be of great importance to give a body/cabin different colour shades* by introducing colour pigments in the thermoplastic material, the layers on the outside and the inside of the body respectively thus obtaining the colour combination(s) desired. This eliminates the traditional outer treatment of a car body consisting of cor¬ rosion protection, polishing, spraying, etc. This will have considerable advan¬ tages from the environmental point of view, since the use of spraying paint and volatile substances is avoided. As mentioned above, the present application provides a very well suited and rational method of utilizing recyclable material, including both ends and remains of new bodies which are moulded, or bodies of discarded vehicles. The problem with the use of regranulated material of this kind is often that it is difficult to combine with a finish, colour and surface which is required by a purchaser. By utilizing this material encapsulated in a laminate, this problem is avoided. The application is a new and unconventional method of using thermoplastic material, and the application permits the use of modern materials in an efficient, rational and environmentally friendly manner. Bodies/cabins fabricated in one piece as described will be very strong due to the edged and angular three dimensional design. This gives the products the necess¬ ary rigidity and strength. Laminates of thermoplastic materials can also be developed by adding to a minimum of one layer of the thermoplastic material a blowing means which causes one layer to be foamed. Thus an example of such a laminate could be one with a fixed homogeneous layer on the outside of the body part, a foamed central layer as a core and a second homogeneous layer on the inside, possibly in a different requested colour. In this way a uniform construction is obtained which provides satisfactory rigidity and strength in addition to giving the body good heat and sound insulation. In this application thermoplastics will be used which are compatible with one another in such a manner that the layers are attached to one another without the addition of adhesive/bonding agents. It is presumed that the thermoplastic laminate will be manufactured by means of known per se production methods such as, for example, rotational moulding. The application is considered to be extremely unconventional in relation to those production methods in use to-day for building car bodies and cabins. The application meets all the requirements for environmentally friendly production and efficient and rational utilization of resource materials. Recycling is therefore an object and a reapplication of such material is achieved by means of the above-mentioned methods. The application also makes it possible to use traditional types of thermoplastic which have a wide range of applications an which are favourable with regard to price.

Claims: PATENT CLAIMS 1. The use of a laminated plastics material, wherein the various layers are thermoplastics which are attached to one another during the moulding process without the use of bonding agents and preferably with at least one foamed thermoplastic layer, for the manufacture of large vehicle body parts or cabins in one piece. 2. The use according to claim 1 wherein one or more of the layers are manufactured by the use of recycled material. 3. The use according to the above claims wherein the layers in the laminate consist of materials with different colour pigments. 4. The use according to the above claims wherein linear low density polyethylene (LLDPE) is employed as a thermoplastic.

Inventors: RINGDAL JAN OTTO, RINGDAL LARS, RINGDAL, JAN, OTTO, RINGDAL, LARS
Applicants: RINGDAL JAN OTTO, RINGDAL LARS, RINGDAL PATENTER AS, RINGDAL PATENTER A/S, RINGDAL, JAN, OTTO, RINGDAL, LARS
Application year: 1994
Main classification: B62D29
IPC codes: B62D23, B62D25, B62D29